Of persons sentenced to imprisonment with or without labor, those under 20 years of age at the time of trial are referred to as juvenile inmates. Sentences for juvenile inmates are executed in juvenile prisons or specifically designated sections in prisons, to prevent adverse influences from adult inmates and ensure sufficient education and training. Juvenile inmates who are under 16 years of age can be treated at juvenile training schools until they reach 16, in accordance with Clause 3, Article 56 of the Juvenile Law, effective as of April 1 of 2001.
  As of April 1, 2001, eight juvenile prisons had been established, in Hakodate, Morioka, Mito, Kawagoe, Matsumoto, Himeji, Nara, and Saga.